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Look! No Mouthpiece! – Passive Alcohol Testing

When we think of alcohol testing we usually visualize someone blowing into a mouthpiece mounted on a breath testing device. This typical method of alcohol testing is called a “direct” test. Some breath test devices have the capability of conducting a different kind of test called a “passive” test. When doing a passive alcohol test the individual does not blow into a mouthpiece, but instead blows towards the device.

Why Passive Alcohol Testing?

Passive alcohol testing allows the operator to quickly screen large groups of people for the presence of alcohol. High school dances, shelters, and substance abuse treatment group meetings. Individuals who have alcohol on their breath can be given a direct breath test to determine their intoxication level.

Qualitative, Not Quantitative

Passive alcohol tests give qualitative results, or pass / fail results. Because the devices are not able to precisely control the volume of breath being measured they are not able to accurately measure intoxication level. They can, however, readily detect whether an individual has alcohol on their breath or not. Some devices, such as the Alco-Sensor FST and the Alco-Sensor VXL, display results as “positive” or “negative.” Other devices, such as thePAS IV flashlight, use a colored bar graph to indicate presence of alcohol at relative concentrations.

How do Passive Alcohol Testers Work?

The passive test devices manufactured by PAS International use a small pump that runs for several seconds, pulling air into the sensor. When testing an individual, the operator instructs the subject to blow at the device as the operator starts the sampling pump. The pump then pulls some of the subject’s breath into the device.

The Alco-Sensor FST and Alco-Sensor VXL use a passive sampling cup in place of a mouthpiece. The cup concentrates a person’s breath into the breath sample port. As the subject blows at the sample cup the force of the breath automatically triggers the Alco-Sensor to sample the breath.

Quick test sequence: Alco-Sensor FST can perform a passive test every 10 seconds. Because the subject does not touch their mouth to the sampling cup the operator does not need to change the cup between negative tests, which also speeds the test process.

Test Beverages for presence of alcohol: If a liquid contains alcohol a small amount of alcohol is constantly evaporating from the liquid and can be detected by the passive device by testing the air just over the surface of the beverage.

Test environment for presence of alcohol: The PAS IV flashlight can be used to detect open alcoholic beverage containers in a car.

AlcoPro carries the following instruments capable of performing passive alcohol testing. Click on each device for more information.